By Wayne J. McLaurinUniversity of GeorgiaMany Georgia gardeners have sliced fresh, crisp, green cucumbers only to find them so bitter they had to throw them away. Occasionally, shoppers find they’ve bought bitter cukes.The compounds that cause bitterness in cucumbers grown in the United States are cucurbitacin B and cucurbitacin C. Wild cucumbers, most of which are extremely bitter, may also contain a number of related compounds.The cucurbitacins occur in all parts of the plant. The leaves, stems and roots of most cultivated varieties contain varying amounts of them. Only occasionally, though, do the bitter compounds spread into the cucumber fruit.Bitterness variesAnd when it does, the bitterness isn’t uniform in the cucumber. It will vary from fruit to fruit and within individual fruits.Two important points: One, the compounds are likely to be more concentrated at the stem end than at the blossom end of the fruit. And two, the bitterness, if it’s there, is always in and just under the skin. It’s not deep in the fleshy portion or in the seed cavity.When using cucumbers for salad, taste a small portion from the stem end of each cucumber before slicing the rest.If it’s bitter, you can usually eliminate the bitterness by removing the outer flesh with the peeling. Peel even more deeply at the stem end, since this is where bitter compounds penetrate most deeply.Many theoriesThe bitterness level in cucumbers varies from year to year. There are many theories, but it has been hard to get consistent information as to its cause.Temperature appears to be one cause. You generally hear more complaints of bitter cucumbers during a cool season than a warm one.Research has shown that fertilization practices, plant spacing and irrigation frequency have little consistent effect on the number of bitter cucumbers produced. Contrary to some people’s belief, the direction of peeling doesn’t affect the spread of bitterness in a cucumber.Grow in sunny sitesWhen growing cucumbers, especially in the cooler parts of Georgia, select a location that’s likely to get as much heat as possible. An area that’s not shaded during any part of the day would be ideal.Even though irrigation practices haven’t proven to greatly affect the number of bitter cucumbers produced, nubbins and other misshapen fruit associated with poor irrigation seem more likely to be bitter than well-shaped fruits.So, provide ample and uniform moisture and adequate nutrients for proper growth. These practices result in rapid, uniform growth of the fruit.Plant for sweet successDifferent cucumber cultivars vary widely in their tendency to be bitter. In tests in several Western states, Improved Long Green, Eversweet, Ashley, Lemon and Saticoy Hybrid had the least bitterness.The best advice for the gardener is to plant varieties that have been shown to produce a low percentage of bitter fruit. Besides the varieties already listed, bitterness hasn’t been a problem in the new, long hybrids that have recently become popular.In general, pickling varieties tend to have more bitter fruits than slicing varieties. However, the amount of bitterness found in commercial pickling varieties in the United States doesn’t seem sufficient to impair flavor in either sweet or dill pickles made from them, even if bitter cucumbers are used.Personally, I think vinegar-and-sliced-Vidalia-onion marinade helps any cucumber taste better.